How can I get a good bal­ance when us­ing dif­fer­ent pat­terns?

It de­pends on the scale of the room. You might think pat­terns wouldn’t work in a small space such as a down­stairs loo or hall, but they can cre­ate more bal­ance – a black-and-white de­sign wall­pa­per sets off colourful art and pat­terned lamp­shades.